Someone told me that mobs doesnt summon if they are snared. i.g. necros could aggrokite mobs who summon and i remember once that i saw a wizzy in SF trying to solo a guardian wurm. i had no time to stay to see if he was knowing what he is doing. So can someone pls explain if snare affects in any way the ability to summon.

You can actually pull any summoning mob with non damaging spells. That includes snare. As a Cleric, I use the reverse damage spell (Mark line of spell) to pull mobs. They have very small aggro so the tank can take aggro right away and they don't do damage so I don't get summoned. One thing I noticed, and someone can correct me this if I am wrong, you will also not be summoned if you nuke and the mob resists the spell thus no damage is done.

As the above poster said, snare is a high aggro spell. So it's possible that you can aggro kite by having the druid or ranger repeatedly snare and kite the mob while rest dot/nuke. That is very possible.